No drama piranha

The red-bellied piranha, also known as the red piranha (Pygocentrus nattereri), is a species of piranha native to South America and a popular aquarium fish. Through media influence, the red-bellied piranha has developed a reputation as a ferocious predator, but scientists believe that the animals’ fearsome reputation has been exaggerated [1].

This week we are releasing the chromosome-length assembly for the red-bellied piranha, based on the work by W.C. Warren and M. Schartl [2]. We are grateful to Moody Gardens for the sample used for Hi-C library preparation!

Check out the alignments of the new assembly to the two most closely related fish genome assemblies out there: the Mexican tetra Astyanax mexicanus, from (McGaugh et al. Nat Commun., 2014), and the channel catfish Ictalurus punctatus, from (Liu et al. Nat Commun., 2016). Looks like the content of the chromosomes is largely preserved.

Whole genome alignments of the red-bellied piranha genome assembly to the assemblies of the Mexican tetra (left) and channel catfish (right).

Turning the leaf for the silkworm caterpillar

Today we are releasing the chromosome-length genome assembly for the silkmoth Bombyx mori. The caterpillar stage of the silkmoth, the silkworm, is a valuable source of silk. A single silkworm produces a single continuous silk thread up to 1,300 meters (4,250 feet) in length, and it takes 1700 to 2000 silkworm cocoons to make one silk dress [1]!

The new genome assembly, shared here, is based on the work from the International Silkworm Genome Consortium (International Silkworm Genome Consortium, Insect Biochemistry and Molecular Biology, 2008). The Hi-C data for the upgrade was generated using insects from the Carolina Biological Supply Company.

To validate the assembly, we compare the positions of 1,451 SNP markers from the Silkworm Genome Research Program website predicted from linkage mapping with their coordinates on the new assembly, below. The datasets are in excellent agreement!

Comparison of SNP marker positions according to the linkage data and predicted by the new assembly.

The eagle has landed

This week we are releasing a genome assembly for the golden eagle, Aquila chrysaetos. The golden eagle is North America's largest bird of prey, and a protected species in the United States.

The chromosome-length assembly is based on the draft from (Van Den Bussche et al., 2017), an important resource for population genomic studies in golden eagles. The sample for Hi-C library preparation used for the upgrade was donated by a female named Bonnie at the Texas State Aquarium.

Check out the alignments against the chicken genome assembly to understand how chromosomes of the golden eagle relate to those of other bird species in the DNA Zoo collection. While we've seen a lot of birds (and non-avian reptiles) displaying a highly conservative karyotype (see, for example, our blog post about the prairie chicken and the band-tailed pigeon), the golden eagle genome tells a very different story, with extensive rearrangements.

Whole-genome alignments of the golden eagle chromosomes to those of chicken (genome assembly GRCg6a, NCBI accession: GCF_000002315.5).